View Compilation Error

0_0_25298076_23863.cpp: In function 'bool read()':
0_0_25298076_23863.cpp:90:20: error: 'n' was not declared in this scope
     for(int i=1;i<=n;++i) scanf("%d%d%d",&p[i].x,&p[i].y,&p[i].z);
                    ^